Another great way to overcome limitations might be the NodeMCU Arduino Pro Mini combination.
The NodeMCU is a combination of powerful microcontroller and a complete WiFi system. It’s great for internet of things (IoT) solutions. The main limitation is with having enough I/O pins to attach peripherals like sensors, motors, displays.
It recently occurred to me that a combination NodeMCU Arduino Pro Mini expansion solution would be worth a try.
The Arduino Pro Mini (shown at right above) is a tiny but full-fledged Arduino for around $2 on EBay. Even better, there is a 3.3V version. This is important because many devices (including NodeMCU) run on 3.3V and their pins are not compatible with the usual Arduino five volts.
Exploring NodeMCU Arduino Pro Mini Combination
Here are some of the key ideas I will try with this combination.
- The main reason for using NodeMCU is its integrated WiFi for remote operation. The two microcontrollers can communicate with each other in a variety of ways. The simplest would be serial or I2C communications, requiring only two pins on each device.
- The programming for your remote solution could be divided between the NodeMCU and the Arduino easily. If you are using Visual Studio and Visual Micro as the IDE, a single VS solution could be used to program both chips.
- Or, you could just use the NodeMCU as the remote WiFi connection. Then pass your commands and data back and forth between the Arduino and the Wifi using the serial bus. This way, the NodeMCU just handles WiFi and the Arduino Pro Mini does all the heavy lifting – reading sensors, running motors, and so on.
- Another benefit of slaving the Arduino in this way would be eliminate watchdog time out problems that occur if you put too much of a processing load on the ESP8266.
Recently, I wrote about expanding the NodeMCU with an I2C GPIO expansion board. But in hindsight, the NodeMCU Arduino Pro Mini combination would give you a more powerful (although perhaps more complex) solution at the same price.